THE INFLUENCE OP CERTAIN ELEMENTS ON THE PHYSICAL PROPERTIES OP STEEL.
Numerous investigations have heen conducted to discover the influence of different elements on the strength and ductility of steel, a common method being to melt definite combinations in crucibles and ascribe the physical result to the known variables. This system will discover the effect of large proportions of certain elements, but it is worthless in the accurate valuation of minute proportions of the metalloids, since small variations in the chemical equation are masked by irregularities in casting and working. The problem is also complicated by numberless combinations of different percentages of the various elements, so that it is difficult to'obtain groups where there is only one variable. It has, therefore, not infrequently happened that inconclusive data have been joined to bad logic, and the conclusions of investigators have been at variance with the teachings of experience. It is not my purpose to enumerate all the deductions of experimenters, but to give a general survey of the situation. In. Part I each element is considered separately, and the views therein advanced are in accord with the general consensus of opinion among metallurgists. Part II gives the result of special investigations into the effect of carbon, manganese, and phosphorus .and a determination of the strength of pure iron.
EFPEOT OP CERTAIN ELEMENTS AS DETERMINED BY GENERAL EXPERIENCE AND BY .THE USUAL METHODS OP INVESTIGATION.
SECTION XVIIa.—Carbon.—The ordinary steel of commerce is carbon-steel; in other words, the distinctive features of two different grades are due to variations in carbon rather than to differences in other elements. There are often wide variations in manganese,